Computer generated aircraft displays have become highly sophisticated and are capable of displaying a substantial amount of flight management, navigation and control information, which gives flight crews more effective control of their aircraft and helps to reduce their workload. This reduction in flight crew workload results in fewer pilot errors and thus enhances flight safety. In this regard, electronic displays, such as Heads-Up Displays (HUDs) and Heads-Down Displays (HDDs), are used in aircraft as Primary Flight Displays to display important flight management, navigation and control information to flight crews.
Primary Flight Displays are computer generated displays that provide flight crews with real-time visual representations of the operational states of their aircraft during flights. For example, an existing Primary Flight Display combines critical flight instrumentation (e.g., altitude, attitude, heading, airspeed, vertical speed instruments) and primary engine instrument indicators into a single, readily interpretable display. As a result, Primary Flight Displays have become effective visual tools for controlling aircraft, reducing pilot workload, increasing situational awareness, and thus improving flight safety overall.
Modern Primary Flight Displays are designed to integrate substantial amounts of flight management, navigation and control information from numerous, diverse sources into one comprehensible display. Such an integrated display includes important flight management, navigation and control information representing, for example, an aircraft's attitude, flight path, airspeed, altitude, terrain features, conformal airport, runway or target information, traffic information, situational awareness information, etc. The primary purpose for providing this vast amount of flight management, navigation and control information in a single display is to increase the flight crews' overall awareness of the current status of their aircrafts' operations and controls. Therefore, an important requirement imposed on the design of Primary Flight Displays is that they provide a balanced presentation of the diverse flight management, navigation and control information displayed to flight crews, in order to improve and ensure the effectiveness and accuracy of the decisions being made.
Certain flight information, such as an aircraft's current pitch, heading, flight path, and target information, is critically important for maintaining proper aircraft safety and control. However, a significant problem that exists with prior art Primary Flight Displays and similar types of displays is that the visual symbols representing this critical flight information are typically displayed at or near the same locations (e.g., in the center) of the display, and some of these symbols can overlap and obscure the view of others. For example, critical pitch and heading information can appear behind a flight path marker on a prior art Primary Flight Display. Consequently, a pilot's view of that pitch and heading information, and any targets or terrain features in that region, can be obscured by the flight path marker on the display, which decreases the effectiveness and accuracy of the flight decisions being made. An example of such a problem is illustrated in FIG. 1, which depicts an existing Primary Flight Display (and similar electronic aircraft displays).
Referring to FIG. 1, display 100 represents a prior art electronic display, such as, for example, a Primary Flight Display in an onboard electronic display system for an aircraft (e.g., HDD). Display 100 shows, among other things, computer generated symbols representing a zero pitch reference line (e.g., commonly referred to as a horizon line) 102, two heading indicators 104a and 104b, a flight path marker (also known as a flight path vector or velocity vector) 106, an airport runway 108, an airspeed scale or tape 110, an altitude scale or tape 112, and terrain (e.g., identified generally as element 113). Essentially, as an aircraft approaches an airport for landing, the pilot locates the intended target (runway 108, in this illustrative example) on display 100, and aims the aircraft in the direction of the target (runway 108). The pilot aims the aircraft at the target, by flying a flight director guidance cue and using the lateral and vertical deviation indications (in addition to target airspeed, etc.) to control the aircraft's movement, which results (among other things) in the target remaining in the close vicinity of the flight path marker symbol 106. All the while, the pilot attempts to keep monitoring the other critical flight information on the display, by viewing such critical flight information symbols representing, for example, the zero pitch reference line 102, the heading (course, track, etc.) indicators 104a and 104b, the digital readouts on the airspeed tape 110 and altitude tape 112, and any other important target information (e.g., approaching aircraft, lateral and vertical deviation information, flight path guidance cue information, etc.) or terrain information (e.g., natural or man-made elevated obstacles) being displayed. Alternatively, if a HUD is being used, the pilot may see an actual runway and/or targets through the HUD screen, along with the overlaid computer generated flight information symbols being displayed.
Notwithstanding the distinct advantages of the use of Primary Flight Displays and similar electronic displays in modern aircraft, display 100 in FIG. 1 illustrates a significant drawback of these types of displays. Specifically, some of the flight information symbols being displayed can overlap other flight information symbols, and the overlapping symbols can obscure the pilot's view of the critical flight information that the pilot needs to see. For example, referring to FIG. 1, a significant portion (e.g., identified generally as “segment” 114) of the zero pitch reference line 102, the underlying terrain (e.g., identified generally as element 115) in that region, and an underlying target (e.g., runway 108) are obscured by the overlap of flight path marker 106. When approaching a runway, multiple flight symbols, such as, for example, heading select symbol, track select symbol, heading readout numbers, heading scales, etc. would typically appear in the vicinity of the flight path marker, thus causing significant visual clutter. Also, as indicated by the compass reading 116, a heading indicator (e.g., “16”) should be displayed approximately halfway between heading indicators 104a (“15”) and 104b (“17”) on the zero pitch reference line 102. However, by its absence, it is apparent that this heading indicator (“16”) is completely obscured by the overlap of flight path marker 106.
Additionally, FIG. 1 shows that the stroke symbology (e.g., zero pitch reference line 102) that coincides with airspeed tape 110 and altitude tape 112 (e.g., identified generally as elements 118 and 120) can interfere with the readings of airspeed and altitude information on these tapes, and can also obscure the pilot's view of any underlying terrain features, targets, or other critical flight information that might be displayed “behind” those tapes. As such, this loss of visual contact of such critical flight information by a pilot decreases the effectiveness and accuracy of the flight decisions being made, and thus increases the possibility that flight management, navigation or control errors can occur. Therefore, it would be advantageous to have a system and method that increases the visibility of critical flight information on an electronic display, such as, for example, a Primary Flight Display, similar electronic aircraft displays, and other types of electronic displays. As described in detail below, the present invention provides such a system and method, which resolves the critical flight information visibility problems encountered by flight crews or operators with existing Primary Flight Displays and other types of prior art electronic displays.